Ducted fan mower deck

ABSTRACT

A mower deck comprises an auxiliary source of pressurized air in order to avoid clipping buildup under the mowing deck, most particularly at the trailing edge of the discharge chute. The auxiliary source of air comes through a cloverleaf shaped hole in the mower deck. The spindle is mounted to the mower deck through this hole, as in conventional mowers. However, unlike conventional mowers, because the hole in the mower deck has a cloverleaf configuration air can flow through the corner portions of the cloverleaf configured hole and act as an auxiliary source of air even though the spindle is mounted to the mower deck through the hole.

This is a continuation of application Ser. No. 08/954,296, filed Oct.17, 1997, now U.S. Pat. No. 5,960,616, which is a divisional of Ser. No.08/424,894, filed Apr. 19, 1995, now U.S. Pat. No. 5,873,225.

FIELD OF THE INVENTION

This invention relates to an improved mower deck.

BACKGROUND OF THE INVENTION

Rotary mower decks typically have a single or multiple blade which cutsvegetation by the rotation of such blades in a controlled area such asunderneath a mower deck. Typically, this mower deck includes a singledischarge chute which faces either to the side or, occasionally, to therear of the associated frame which supports same for travel over theground. These mower decks need a large volume of air in order to providefor the movement of grass clippings underneath the deck and through thedischarge chute. Typically, this volume of air is provided by having thelower lip of the lower deck spaced from the ground such that the neededair can travel between the mower deck and the ground before being passedthrough the discharge chute. However, this distance provides for a spacewherein the noise of the blades can pass to the outside world and, inaddition, limits the shortest length of cut for the blades.

OBJECTS OF SUMMARY OF THE INVENTION

It is an object of this present invention to increase the efficiency ofmower decks.

It is another object of the present invention to allow for increaseddepth of the sidewall of a mower deck.

It is yet another object to the present invention to increase theefficiency of the dispersal of grass clippings in a mower deck.

It is still another object of present invention to reduce the pluggingand/or to grass built-up within the confines of the mower deck.

It is a further object of the present invention to increase the baggingefficiency of mower decks.

Other objects and more complete understanding of the invention may behad by referring to the drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

Structure, operation, and advantages are presently disclosed preferredembodiment of the invention will become apparent when consideration ofthe following description take in conjunction with the accompanyingdrawings wherein:

FIG. 1 is a diagram of the airflow created by the invention in a mowerdeck.

FIG. 2 is an enlarged drawing of the area of the trailing edge of themower deck diagram of FIG. 1.

FIG. 3 is a downward-looking view of a mower deck incorporating theinvention of he application,

FIG. 4 is a perspective view of the mower deck of FIG. 3, and

FIG. 5 is an enlargement of the area surrounding the spindle of themower deck of FIG. 3.

DETAILED DESCRIPTION O

F THE INVENTION The invention of this application is directed to the useof high-pressure air in order to improve the cutting efficiency ofrotary lawn mowers. The invention has particular application to lawnmowers having cutting decks extremely close to the ground and/or decksotherwise having a reduced volume of air passing through the deck and/orout the discharge chute. The invention will be described in anembodiment incorporating a single 30 inch blade in a rear discharge typeriding lawn mower.

The invention of this application relates to incorporation of a pressuredifferential creating device to be associated with a mower deck 50having a discharge chute 51 and a rotary blade 52.

In the typical mower deck, when the blade is rotated at slow speeds,operated under heavy loading conditions and/or the deck is deprived of arapid-flow of replacement air, there is a tendency to clog or build upgrass clumps throughout the confines of the mower deck; mostparticularly at the trailing edge 54 of the discharge chute. It is atthis location that any build up is particularly troublesome because, asgrass clippings built up at this location, they also reduce thecross-sectional area of the discharge chute and disrupt the laminar flowof the circulating air around the confines of the mower deck.

The present invention alleviates this problem by incorporating anadditional pressure differential creating device with the mower deck,such pressure differential device increasing the pressure and velocityof air underneath the mower deck, most particularly at the trailing edge54 of the discharge chute. This pressure differential device acts toincrease the velocity of air underneath the mower deck as well asencouraging the vegetation residue to travel through the discharge chute51 and not build up at the trialing edge 54 or elsewhere.

In the preferred embodiment, the mower deck 50 is a 30 inchsingle-bladed rear discharge mower deck for use with a riding lawnmower. Although this particular deck is a single-bladed rear dischargedesign, it could be understood that the invention could be utilized withside-to-side multiple spindle mower decks as well as other rotary mowerdevices that could utilize an increase in pressure differential, mostparticularly at the trailing edge of a discharge chute. These mowerdecks may be suspended from the underneath of a riding mower, may beinterconnected to the front, or may be interconnected to the back of theassociated power vehicle as known in the art.

The particular mower deck 50 disclosed also includes sidewalls 53 whichextend downward into the vegetation further than in ordinary mowerdecks. The purpose for this particular additional extension is to reducethe blade noise which escapes from underneath the mower deck 50. Whileadvantageous, this extension of the sidewall 53 downward also has theeffect of further reducing the amount of air which can be utilized bythe blade otherwise used to create a high enough velocity air flow toprovide for satisfactory mowing under all conditions. Particularlytroublesome are wet lawns having a high blue grass or other high densityconcentration of grass blades.

In even a conventional deck, under these circumstances, the air flowcaused by the rotary blade 52 underneath the mower deck would bedisrupted, causing vegetation build-up on the trialing edge 54 of thedischarge chute 51 and otherwise clogging up the laminar air flow whichwould preferably be present for smooth discharge. With the increasedsidewalls of the present preferred embodiment the problem wouldotherwise be exacerbated.

The present differential pressure device remedies these problems byproviding an extra source of high velocity air underneath the dischargechute and, most particularly, of the trailing edge 54 of the dischargechute 51. This pressure differential device increases the apparentvelocity of air at the discharge chute, this to increase the dischargeefficiency at this critical point while also protecting the trailingedge 54 of the discharge chute against undesired residue buildup. Thetrailing edge 54 is the edge located where the discharge chute 51 andthe sidewall 53 meet.

As shown in FIG. 2 the direction and location of the pressurized air inrespect to the trailing edge of the discharge chute can vary. The mostefficient location is tangential 56 to the path of the mower bladedirected straight at the trailing edge or slightly upstream thereof.This creates a relatively high pressure air stream at this location thusencouraging the grass clippings to pass out of the discharge chute. Asrepresented in FIG. 2, the actual location and direction of the airstream may vary. Keeping the air stream direction the same, movementradially of the center of the mower deck has a minimal additional effecton the air flow. However, angling the air flow at an angle greater thantangential (i.e. over 90 deg. in respect to a radial line to the pointof departure) causes a certain amount of parasitical power loss viaconflicting air streams (and thus is not preferred). An angle of plus orminus 20°, is disclosed, as is a radial displacement 57 of plus 3 minus1.5 inches (in a 30″ deck), both taken in respect to the tangent 56 (seeFIG. 2). In general the greater the radial displacement, the lesser theangle should be and the higher the auxiliary air pressure must be (andvice-versa).

The pressurized air can be provided by any motor driven fan, eitherintegral with the mower deck or separate therefrom. For example, a smallseparate blower mounted above the mower deck and driven by a belt wouldbe appropriate in units where the size and complexity of an integral fancauses design compromises such as multi-spindle side by side mowerdecks.

The particular pressure differential device disclosed is a radial fan 15formed integrally with the spindle 60 of the rotary blade 52 in aconfined space 58 on the underside of the top 55 of the mower deck. Itis preferred that the space 58 is created through the addition of asupplemental piece 61 which is separately bolted to the bottom of themower deck 50 so as to not disturb the integrity of the top 55 of themower deck, most particularly at the critcal location of the mounting ofthe spindle 60.

In that the particular pressure differential device disclosed is radicalfan 15, the supplemental piece 61 is mounted off center in respect tothe axis of rotation of the radial fan so as to provide a increasingcross section generally spiraling air passage or duct 65 surrounding theradial fan. The smallest cross-section 62 of this air passage 65 islocated at or slightly downward of the critical trailing edge 54 of thedischarge chute with the longitudinal axis of the air passage or ductrunning through the trailing edge of the discharge chute. The fanopening 66 being located near to the discharge chute directedtangentially substantially toward or slightly upstream of the trailingedge 54 of the discharge chute 51. In this respect it is noted that theminimum diameter cross sectional area 62 encourages the flow of airthrough the fan opening 66 by creating an air restriction downstream ofthe fan opening. Further, the generally spiraling air passage 65produces a smooth laminar flow of air out of the fan opening 66, thusmaximizing the efficiency of the air flow at this particular location.

In the particular embodiment disclosed, since the fan is a radial fan15, it obtains its source of air through a series of hole 70 provided inthe top 55 of the mower deck nearest the central axis of rotation of theradial fan. This hole 70 allows for the radial fan to pull air therefromand thence outward, thus pressurizing the air in the increasing crosssection spiraling air passage 65.

The holes 70 in the present invention of a unique configuration so as tomaximize deck strength while reducing manufacturing complexity. Inspecific, in the normal mowing deck the spindle is mounted in a centralcircular hole having an inner diameter only slightly more than the outerdiameter of the spindle.

While it is technically possible for one to merely enlarge the centralhole or add additional surrounding holes to provide a source of air forthe fan 15, these both reduce the strength of the deck as well as,especially for the former, increasing the size, cost and complexity ofthe spindle (which now has to be self supporting over a longer distancethan otherwise). In contrast in the present invention the hole 70 is ofcloverleaf 72 configuration complementing the four support arms 100 ofthe spindle 60. The center portion 104 of the cloverleaf configured holeis covered by the spindle. Thus, like the circular hole in conventionalmower decks, very little air can pass through this center portion of thehole. However, each of the four corner portions 106 of the cloverleafconfigured hole are not covered by the spindle and thus air can passthrough them. The edge of the mower deck 101 surrounding the centerportion 104 of the hole has deck holes 103 in it for receiving amounting means for mounting the spindle 60 to the mower deck.

The spindle 60 has support arms 100. Each support arm 100 has a supportarm hole 105 in it for receiving a mounting means to mount the spindleto the mower deck. The deck holes 103 and the support arm holes 105 arealignable for receiving a mounting means to mount the spindle to themower deck. One way that the deck holes 103 and support arm holes 105can be fashioned is by the use of a conventional drill. The mountingmeans can be a screw, bolt, nail, rivet or any other mounting means. Theedges of the cloverleaf 72 are folded (down preferably) so as to createreinforcing flanges 102—thus, stiffening the deck at this criticallocation (the hole shape would vary dependent on the spindle). Thisconfiguration allows the drive spindle 60 to remain the same size as ina conventional deck without compromising the strength of the unit whilestill providing the needed air passage. By having the spindle in such alocation, the air passing over it also cools the critical bearings andkeeps the belt area cleaner than otherwise.

Although the invention has been described as preferred embodiment in acertain degree of particularity, it is understood that numerous changescan be made without deviating from the invention as hereinafter claimed.

What is claimed is:
 1. In a rotary mower deck having a discharge chutewith a trailing edge, the improvement comprising an additional source ofpressurized air and means to direct said pressurized towards thetrailing edge of the discharge chute, said additional source ofpressurized air rotating in a substantially parallel plane to the planeof the mower deck, such that associated grass clippings are dischargedsubstantially through an opening defined by the top of the mower deckand progress through the discharge chute, said additional source ofpressurized air being located in said duct.
 2. The improvement of claim1 characterized in that said source of pressurized air includes a mowerdriver fan.
 3. The improvement of claim 2 wherein the mower deckincludes a blade spindle driven by a mower and characterized in thatsaid mower driver fan is connected to the blade spindle.
 4. Theimprovement of claim 1 wherein the mower deck includes a blade rotatingin a direction towards the trailing inner edge of the discharge chuteand characterized in that said means to direct said pressurized airdirects air in the same direction as the blade.
 5. The improvement ofclaim 3, wherein the blade spindle rotates in a direction andcharacterized in that said duct has a cross section, and said crosssection increasing in the direction of rotation of the blade spindle tothe trailing edge of the discharge chute.
 6. The improvement of claim 2wherein the mower deck has a top surface and characterized by theaddition of holes in the top surface, and in that said fan draws airthrough said holes in the top surface.
 7. In a rotary mower deck havinga rotary blade causing an air flow through a discharge chute with atrialing edge, the improvement comprising: a source of additionalpressurized air; means to direct said additional pressurized air towardsthe trailing edge of the discharge chute, said source of additionalpressurized air including a mower driven fan, said means to direct saidadditional pressurized air including a duct, said mower driven fanlocated in said duct, said mower driven fan rotating in a substantiallyparallel plane to the plane of the mower deck.
 8. The improvement ofclaim 7 wherein a blade spindle rotates in a direction and characterizedin that said duct has a lateral cross-section, and said lateralcross-section increasing in the direction of rotation of said bladespindle to said trailing edge of said discharge chute.
 9. Theimprovement of claim 7 wherein the mower deck has a top surface andcharacterized by the addition of holes in the top surface, and in thatsaid fan drawing air through said holes in the top surface.
 10. In arotary mower deck having a rotary blade causing an air flow through adischarge chute with a trailing edge, the improvement comprising: asource of additional pressurized air; means to direct said additionalpressurized air towards the trailing edge of the discharge chute, saidsource of additional pressurized air including a mower driven fan, saidmower driven fan being connected to a blade spindle, said mower drivenfan rotating in a substantially parallel plane to the plane of the mowerdeck said mower driven fan being located in a duct, said duct having anend opening, said duct having a longitudinal axis through said endopening, said longitudinal axis of said duct substantially runningthrough the trailing edge of the discharge chute, said duct having alateral width cross-section, said lateral width cross-section increasingin the direction of rotation of the blade spindle to the trialing edgeof the discharge chute; and, the mower deck having a top surface, holesin said top surface of said mower deck, and said fan drawing air throughsaid holes in said top surface.